In this paper, the recent realization of topological electronic states such as Dirac and Weyl fermions in real materials and their potential for future energy and electronics applications has motivated interest in the study of new forms of topological behavior embodied through new materials. Pd 3Pb is one such candidate predicted recently to host unique topological features, including a dispersionless band near the Fermi level and triple nodal points hosting Dirac fermions and open Fermi arcs. Here, we report the crystal growth and electric transport properties of Pd 3Pb. Our low field magnetoresistance measurements indicate an anisotropic Fermi surface. We found that Pd 3Pb manifests a large transverse magnetoresistance, which reaches 650% at 1.8 K and 14 T, and pronounced Shubnikov-de Haas (SdH) oscillations. Preliminary analysis of the field dependence of the SdH oscillations points to the likelihood of nontrivial Berry phase in Pd 3Pb. Further studies in high field limit are desirable to extend the realization of the topological properties of the predicted novel fermions in this material.

@article{osti_1471586,
title = {Anisotropic angular magnetoresistance and Fermi surface topology of the candidate novel topological metal Pd3Pb},
author = {Ghimire, N. J. and Khan, Mojammel A. and Botana, A. S. and Jiang, J. S. and Mitchell, J. F.},
abstractNote = {In this paper, the recent realization of topological electronic states such as Dirac and Weyl fermions in real materials and their potential for future energy and electronics applications has motivated interest in the study of new forms of topological behavior embodied through new materials. Pd3Pb is one such candidate predicted recently to host unique topological features, including a dispersionless band near the Fermi level and triple nodal points hosting Dirac fermions and open Fermi arcs. Here, we report the crystal growth and electric transport properties of Pd3Pb. Our low field magnetoresistance measurements indicate an anisotropic Fermi surface. We found that Pd3Pb manifests a large transverse magnetoresistance, which reaches 650% at 1.8 K and 14 T, and pronounced Shubnikov-de Haas (SdH) oscillations. Preliminary analysis of the field dependence of the SdH oscillations points to the likelihood of nontrivial Berry phase in Pd3Pb. Further studies in high field limit are desirable to extend the realization of the topological properties of the predicted novel fermions in this material.},
doi = {10.1103/PhysRevMaterials.2.081201},
journal = {Physical Review Materials},
number = 8,
volume = 2,
place = {United States},
year = {2018},
month = {8}
}

We used low-energy, momentum-resolved inelastic electron scattering to study surface collective modes of the three-dimensional topological insulators Bi 2Se 3 and Bi 0.5Sb 1.5Te 3-xSe x . Our goal was to identify the “spin plasmon” predicted by Raghu and co-workers [Phys. Rev. Lett. 104, 116401 (2010)]. Instead, we found that the primary collective mode is a surface plasmon arising from the bulk, free carriers in these materials. This excitation dominates the spectral weight in the bosonic function of the surface χ '' ( q , ω ) at THz energy scales, and is the most likely origin of a quasiparticlemore » dispersion kink observed in previous photoemission experiments. Our study suggests that the spin plasmon may mix with this other surface mode, calling for a more nuanced understanding of optical experiments in which the spin plasmon is reported to play a role.« less

We used low-energy, momentum-resolved inelastic electron scattering to study surface collective modes of the three-dimensional topological insulators Bi 2 Se 3 and Bi 0.5 Sb 1.5 Te 3 - x Se x . Our goal was to identify the “spin plasmon” predicted by Raghu and co-workers [Phys. Rev. Lett. 104, 116401 (2010)]. Instead, we found that the primary collective mode is a surface plasmon arising from the bulk, free carriers in these materials. This excitation dominates the spectral weight in the bosonic function of the surface χ '' ( q , ω ) at THz energy scales, and is themore » most likely origin of a quasiparticle dispersion kink observed in previous photoemission experiments. Our study suggests that the spin plasmon may mix with this other surface mode, calling for a more nuanced understanding of optical experiments in which the spin plasmon is reported to play a role« less

Here, the monoclinic (M) phases in high-performance relaxor-based ferroelectric single crystals have been recognized to be a vital structural factor for the outstanding piezoelectric property. However, due to the complexity of the structure in M phases, the understanding about it is still limited. In this paper, the local twin domains and tip-voltage-induced domain switching of the M C phase in Pb(Mg 1/3Nb 2/3)O 3 - 0.34PbTiO 3 (PMN-0.34PT) single crystal have been intensively investigated by piezoresponse force microscopy (PFM). By theoretically analyzing the experimental patterns of domain walls on the (001) C face, the specific M C twin domains inmore » the initial annealed state of a selected area have been clarified, and the polarization orientation of the M C phase in this sample is determined to be at an angle of 29 degrees to the < 001 > C directions. In addition, based on the evolution of domains and the motion of domain walls under the step-increased PFM tip dc voltage (V dc), the switching process and features of different types of M C domain variants are visually revealed« less